[1] He set up a gallery called F. Kleinberger Galleries at 9 Rue de l’Échelle in Paris, either in January, 1883, or on February 15, 1883, principally involved in selling to US buyers.
Here is the source for the obviously wrong year of opening his gallery in Paris.
[2] By 1913, according another source after the First World War, he had set up a gallery on lower (first at No.
[3] He was the intermediary in the purchase of Fabritius's The Goldfinch by art collector Abraham Bredius for 6,200 francs at the sale of the Émile Martinet collection on 27 February 1896.
[I let Kleinb[e]rger bid at the auction ... the gentleman turned around and said, "now I would like to know who the buyer is!"